Effect of trehalose- an impermeant cryoprotectant on cryopreservation of Black Bengal buck semen

The experiment was conducted to study the effect of trehalose an impermeant extra cellular cryoprotectant supplementation on cryopreservation of Black Bengal buck semen. Semen ejaculates (n = 24) were diluted in Tris- soybean lecithin - glycerol extender having trehalose @ 0, 50,100and 150 mM. Samples were equilibrated at 5°C for 3 hrs, frozen and stored in liquid nitrogen. Semen samples were evaluated for sperm motility,functional membrane integrityand concentration of lipid peroxide compound malondialdehyde at three stages such as 10 minsafter dilution with extender, after completion of equilibration period and after freeze thawing. It was found that the control group (0mM trehalose)had significantly better in vitro sperm characters when compared to extenders supplemented with trehalose (50 mM , 100 mM and 150 mM) during different stages of cryopreservation. It can be concluded that supplementation of trehaloseas a cryoprotectant did not improve the cryopreservability of Black Bengal buck semen.

The formation of ferric haem during low-temperature photolysis of horseradish peroxidase Compound I

Illumination at low temperature of the peroxide compound of horseradish peroxidase (HRP-I) causes partial conversion of the haem electronic structure from a ferryl-porphyrin radical species into a low-spin ferric state. Magnetic-c.d. (m.c.d.) and e.p.r. spectral features of the photolysis product are almost identical with those of the alkaline form of ferric HRP, proposed on the basis of its near-i.r. m.c.d. spectrum to be a Fe(III)-OH species. The ferric product of HRP-I photolysis also contains free-radical e.p.r. signals. Conversion of HRP-I into the Fe(III)-OH species, which requires transfer of a proton and two electrons from the protein, is shown to be a two-step process.